Quantifying the effects of urban development intensity on the surface urban heat island across building climate zones

Urban heat island (UHI) has gradually been a critical issue in the context of global environmental change and regional sustainability. The urban development intensity (UDI) increases with rapid urbanization and exacerbates the UHI problem, but the effects and contributions of UDI on UHI remain unclear. Based on Landsat 8 satellite images, this study quantified the effects of UDI on surface UHI intensity (SUHII) in 20 important cities across 5 building climate zones of China by using regression analysis, correlation analysis and boosted regression tree (BRT), and analyzed their potential influence mechanisms. Results indicated that there was apparent spatial heterogeneity of SUHII in different building climate zones (ranging from 3.26 degrees C to 4.43 degrees C) and cities (ranging from 1.44 degrees C to 6.61 degrees C). The effect of UDI on SHUII in cities of north was stronger than that in south, the average R2 values of the UDI-SUHII relationship in severe cold zone and cold zone were higher than the other climate zones. Building density, as the most critical predictor of SUHII among UDI metrics in all cities, was significantly positively correlated with SUHII. The R2 values showed significant positive correlation with annual average sunshine duration and aridity, and significant negative correlation with annual average precipitation, humidity and soil clay content. Our findings can offer new insights and decision-support in climate-adapted urban planning and heat-related risk management across different building climate zones.